C# 9 init properties, error example.

Program.cs

using System;

var glasgowMeetup = new Meetup() {
    City ="Glasgow",
    Topic = ".Net"
};

glasgowMeetup.Topic = "Umbraco";
glasgowMeetup.City = "Edinburgh";

Console.WriteLine(glasgowMeetup);

public record Meetup 
{ 
    public string City { get; init; }
    public string Topic { get; set; }
}